What star can not after its run out of fuel?

A star that cannot undergo further fusion after it has exhausted its nuclear fuel is a white dwarf. Once a star like our Sun has burned through its hydrogen and helium, it sheds its outer layers, leaving behind a hot core that cools over time. This remnant is no longer capable of nuclear fusion and will gradually fade away as it radiates its remaining heat into space. Eventually, it will become a cold, dark object known as a black dwarf, although the universe is not old enough for any black dwarfs to exist yet.